Copper speciation and total essential trace element levels in Wilson's disease

Wilson's disease (WD) is a rare genetic disorder characterized by impaired Cu metabolism in the body. This study aimed to compare the total levels of essential trace elements (Cr, Mn, Fe, Co, Cu, Zn, Se, and Mo) in plasma and urine samples of WD-treated patients (cases) and healthy controls, and to conduct Cu speciation in plasma samples. Inductively coupled plasma mass spectrometry (ICP-MS) was used for total element concentration, while high-performance liquid chromatography (HPLC) coupled to ICP-MS (HPLC-ICP-MS) was used to determine the following Cu species: Cu-ceruloplasmin (Cu-Cp), Cu-human serum albumin (Cu-HSA), and Cu-low molecular mass (Cu-LMM). In plasma, cases had significantly lower levels of Cu, but higher levels of Zn and Se than controls. In urine, cases had significantly higher levels of Cu and Zn, while the levels of Se, Co, and Mo were significantly lower than in controls. Therapy with ZnSO₄ led to higher plasma Zn and Se levels, and higher urine Zn levels, while chelating agent therapy increased urine Cu levels. Among the three Cu species in both cases and controls, the proportion of Cu-Cp was the most dominant, followed by Cu-HSA and Cu-LMM. Long-term drug therapy led to a decline or loss of Cu-HSA and Cu-LMM fractions, offering opportunities for potential plasma biomarkers of WD. Overall, this study provides new insight into the levels of essential trace elements in the plasma and urine of WD-treated cases, the impact of drug therapy on the alteration of specific trace elements and three major species of Cu, potential new biomarkers, and the implications for careful monitoring of drug therapy in WD patients.